@article{frank_klein_costa_2007, 
  title={IFDMA: A Scheme Combining the Advantages of OFDMA and CDMA}, 
  volume={14}, 
  DOI={10.1109/mwc.2007.386607}, 
  publisher={Institute of Electrical and Electronics Engineers (IEEE)}, 
  author={Frank and Klein and Costa}, 
  year={2007}
  }